/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.model;

import javax.xml.stream.XMLStreamException;

import net.sf.freecol.common.io.FreeColXMLReader;
import net.sf.freecol.common.io.FreeColXMLWriter;

import org.w3c.dom.Element;


/**
 * This class contains the last sale a player has made, by Settlement
 * and GoodsType.
 */
public final class LastSale extends FreeColObject
{

    /** When a sale was made. */
    private Turn when;

    /** The price per unit returned from the sale. */
    private int price;


    /**
     * Make a new LastSale record.
     *
     * @param where The <code>Location</code> of the sale.
     * @param what The <code>GoodsType</code> sold.
     * @param when In which <code>Turn</code> the sale occurred.
     * @param price The per-unit price of the sale.
     */
    public LastSale( Location where, GoodsType what,
                     Turn when, int price )
    {
        this( makeKey( where, what ), when, price );
    }

    /**
     * Make a new LastSale record.
     *
     * @param id The object identifier.
     * @param when In which <code>Turn</code> the sale occurred.
     * @param price The per-unit price of the sale.
     */
    public LastSale( String id, Turn when, int price )
    {
        setId( id );
        this.when = when;
        this.price = price;
    }

    /**
     * Create a new last sale by reading a stream.
     *
     * @param xr The <code>FreeColXMLReader</code> to read from.
     * @exception XMLStreamException if there is a problem reading the stream.
     */
    public LastSale( FreeColXMLReader xr ) throws XMLStreamException
    {
        readFromXML( xr );
    }

    /**
     * Create a new last sale by reading an element.
     *
     * @param element The <code>Element</code> to read from.
     */
    public LastSale( Element element )
    {
        readFromXMLElement( element );
    }


    /**
     * Get the <code>Turn</code> when the sale was made.
     *
     * @return The <code>Turn</code> when the sale was made.
     */
    public Turn getWhen( )
    {
        return when;
    }

    /**
     * Get the price from the sale.
     *
     * @return The price from the sale.
     */
    public int getPrice( )
    {
        return price;
    }

    /**
     * Make a String to be used as a key for looking up sales.
     *
     * @param where The <code>Location</code> of the sale.
     * @param what The <code>GoodsType</code> sold.
     *
     * @return A key string.
     */
    public static String makeKey( Location where, GoodsType what )
    {
        return where.getId( ) + "-" + what.getId( );
    }


    // Override FreeColObject

    /**
     * {@inheritDoc}
     */
    @Override
    public int compareTo( FreeColObject other )
    {
        int cmp = 0;
        if ( other instanceof LastSale )
        {
            LastSale ls = ( LastSale ) other;
            cmp = getWhen( ).getNumber( ) - ls.getWhen( ).getNumber( );
        }
        if ( cmp == 0 ) cmp = super.compareTo( other );
        return cmp;
    }


    // Serialization

    private static final String PRICE_TAG = "price";
    private static final String WHEN_TAG = "when";


    /**
     * {@inheritDoc}
     */
    @Override
    protected void writeAttributes( FreeColXMLWriter xw ) throws XMLStreamException
    {
        super.writeAttributes( xw );

        xw.writeAttribute( WHEN_TAG, when.getNumber( ) );

        xw.writeAttribute( PRICE_TAG, price );
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void readAttributes( FreeColXMLReader xr ) throws XMLStreamException
    {
        super.readAttributes( xr );

        when = new Turn( xr.getAttribute( WHEN_TAG, 0 ) );

        price = xr.getAttribute( PRICE_TAG, 0 );
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString( )
    {
        StringBuilder sb = new StringBuilder( 32 );
        sb.append( "[" ).append( getId( ) )
                .append( " when=" ).append( when )
                .append( " price=" ).append( price )
                .append( "]" );
        return sb.toString( );
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getXMLTagName( ) { return getXMLElementTagName( ); }

    /**
     * Gets the tag name of the root element representing this object.
     *
     * @return "lastSale"
     */
    public static String getXMLElementTagName( )
    {
        return "lastSale";
    }
}
